I just did a sale the last week of June. Here is what I found in my area:
Yes, price everything. Most people won't take the time to ask you, and it's likely that you will be busy at your check-out table. The only thing we didn't price individually was a rack of adult clothes. We put a big sign that said, "All adult clothing $1.00 per item."
An easy way to price is to get some address labels (a sheet of 1" x 2 5/8" has 30 on it) and print a sheet of $1, $2, etc. You can fit 2-3 dollar amounts per label. Then just cut them apart. They stick well but also come off well when it's time.
Also, for ease of adding, don't price anything under $.25 (I can't find the cents symbol on my computer!). Anything you think isn't worth a quarter, put in a basket labeled FREE. Or I also labeled some travel mugs FREE (we a ton of them) and put them on a table with other priced items. They all went and I just wanted them out of my cupboard!
We did Friday 8 - 1. We were steadily busy with a few lulls mixed in right up until the end. Saturday we did 8-12. Not one person came until 9:30. I think they all went to check out the Saturday only sales first, and then trickled in to see what we had left. We were lucky to sell $100 worth of stuff on the second day. Still worth it to me, though, because everything was already set up and I did get rid of more stuff.....and $100 is a $100.
I know it's hard, but try to be as organized as possible. We had a lot of comments about how well organized and clean our sale was (truly, thanks to my sister!). It makes it easier for people to shop when they don't have to dig. And if the presentation gives a feeling of being clean, then they will assume you are a "clean" person, which means your stuff has been well-taken care of which means they want to buy it!
Good luck!